Everybody knows that smaller is better when we consider the development of an internal artificial organ system. For the development of smaller and light weight internal artificial organs, micromachining technology and nano technology will have the possibility of the usefulness. For example, artificial sphincter, artificial esophagus, super stent system, convulsion stop machine, artificial heart, ventricular assist device, artificial myocardium system are now under development by the use of various kinds of nano technologies. Furthermore, implantable artificial organ system enables the patients to come back to their homes. So, not only for the life of the patients, but also for the QOL of the patients, nanotechnology will be useful in the development in near future.